Steam generator



FIG. 1 is a perspective view of a steam generator showing our new design;

FIG. 2 is a left side view thereof

FIG. 3 is a right side view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a rear view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken line portions of the drawings are included to show portions of the article that form no part of the claimed invention. 

CLAIM The ornamental design for a steam generator, as shown and described. 